1. Field of the Invention
The present invention relates to an illumination device and a method for manufacturing the illumination device, more specifically, to an illumination device utilizable as a backlight for a liquid crystal display or a flash light which is installed in mobile phones, mobile information terminals or the like and a method for manufacturing the illumination device.
2. Description of the Related Art
Because recent that mobile terminals such as mobile phones, cameras, mobile information terminals, or the like are required to be miniaturized, a small liquid crystal display having a low power consumption is often used in a display section. The liquid crystal display often includes an edge light-type backlight with a light-guiding plate configured to introduce light from a light source through a side surface of the light-guiding plate to illuminate the display so that characters or images are visible even in a dark place. Such a backlight conventionally includes a planar light-guiding plate with a light-emitting diode (LED) disposed to face a side surface of the light-guiding plate, and a backlight in which an LED is contained in a concave portion provided in the light-guiding plate at a lower surface thereof has been disclosed (for reference, see Japanese Patent Application Publication No. 2001-67917, pages 3 and 4, FIGS. 1 to 3).
A specific structure of an illumination device used as a conventional backlight is described hereinafter with reference to FIGS. 19A to 19C.
As shown in FIGS. 19A to 19C, a conventional illumination device to illuminate a liquid crystal display panel 200 includes a light-guiding plate 1 disposed to face a lower surface of the liquid crystal display panel 200 and an LED element 2 mounted on a flexible substrate 3 and contained in a concave portion 1a which is provided in a lower surface adjacent to one side edge of the light-guiding plate 1.
The lower surface of the light-guiding plate 1 is provided with a scattering reflection layer 1b having an area corresponding to a size of the liquid crystal display panel 200 and including fine concave and convex patterns. A reflection sheet 4 is provided on an upper surface of the light-guiding plate 1 at a position opposite to the concave portion 1a of the lower surface of the light-guiding plate 1. The LED element 2 is bonded to printed wiring patterns on the flexible substrate 3 through wires 2a. A sealing resin layer 6 is provided in the concave portion 1a to seal the LED element 2 in the concave portion 1a. 
Note that the flexible substrate 3 is fixed to the light-guiding plate 1 through a reinforcing plate 5 and thus, the flexible substrate 3 is integrated with the light-guiding plate 1. A leading end portion of the flexible substrate 3 is disposed on the lower surface of the light-guiding plate 1 and the LED element 2 is contained in the concave portion 1a. In the illumination device having the aforementioned structure, light emitted from the LED element 2 is guided in the light-guiding plate 1 and emitted from a light emission surface of the light-guiding plate 1 to illuminate the liquid crystal display panel 200.
However, in this structure mentioned above, there are problems that the processes of manufacturing the illumination device include a large number of hand operations such as adherences or the like, variations in quality may arise, and production costs may increase.